Parenterally administered penicillin

Parenterally administered penicillin is recommended for all stages of syphilis. Alternative agents may be used in allergic individuals and include doxycycline, minocycline, tetracycline, or erythromycin base or stearate. Some patients may not respond favorably to alternative modalities. Therefore, in patients who must be administered penicillin (i.e., patients who are pregnant or have central nervous system [CNS] involvement) or are allergic, desensitization must be performed before the drug is initiated. 

The answer is a. (Hardman, pp 1143-1144.) Polymyxin B is poorly absorbed by the oral route. It is primarily administered by the topical route for the treatment of infections of the skin, mucous membranes, eye, and ear. Penicillin G can be administered both orally and parenterally. Did oxacillin is only given by the oral route. Carbenicillin and streptomycin are administered only by the parenteral route. 

In penicillin-allergic patients, oral or parenteral clindamycin may be used. Alternatively, a first-generation cephalosporin such as cefazolin (1 to 2 g IV every 6 to 8 hours) may be used cautiously for patients who have not experienced immediate or anaphylactic penicillin reactions and are penicillin skin test negative. In severe cases in which cephalosporins cannot be used because of documented methicillin resistance or severe allergic reactions to /1-lactam antibiotics, IV vancomycin should be administered. 

Mezlocillin, piperacillin, and ticarcillin are parenteral antibiotics formulated as sodium salts, so prescribers must consider the sodium content of these antibiotics when administering them to patients with congestive heart failure. During their distribution phase, antipseudomonal penicillins achieve orfly low concentrations in the cerebrospinal fluid. Consequently, antipseudomonal penicillins are not among the drugs of first choice for meningitis therapy. 

Oxacillin, cloxacillin, and dicloxacillin are all semisynthetic isoxazolyl penicillins suitably modified to be relatively resistant to hydrolysis by staphylococcal -lactamase. They have the additional advantage of being stable in the presence of gastric acid, so they can be administered orally as well as parenterally. 

Cefazolin is a first-generation cephalosporin with antibacterial activity similar to that of penicillin G but it is -lactamase-resistant. It is poorly absorbed from the gastrointestinal tract and, thus, it is primarily administered parenterally. It is widely used for ticatment of mastitis in lactating cows, sheep, and goats and for treatment at drying off by the intramammary route. 

V) can be administered orally but have a relatively narrow antibacterial spectrum. Some semisynthetic penicillins (amoxicillin, ampicillin) have a broader antibacterial spectrum and may be administered either orally or parenterally, depending on the specific agent. 

It has also been reported that patients with allergic-like events after penicillin treatment have had a markedly risk of events after subsequent cephalosporin antibiotics. Cross-reactivity is not an adequate explanation for this increased risk and the data obtained indicate that cephalosporins can be considered for patients with penicillin allergy <2006MI354.ell>. Comparisons of parenteral broad-spectrum cephalosporins have been tested against bacteria isolated from pediatric patients. The results have indicated that cefepime has been the most broad-spectrum cephalosporin analyzed and it is a very potent alternative for the treatment of contemporary pediatric infections in North America <2007MI109>. The historical safety of the most commonly used oral cephalosporins has been reviewed <2007MIS67>. The antimicrobial spectrum and in vitro potency of the most frequently prescribed orally administered cephalosporins (cefaclor, cefdinir, cefpodoxime, cefprozil, cefuroxime axetil and cephalexin has also been reviewed <2007MIS5>. 

Correct answer = A. Most urinary tract infections are due to E. coii and can usually be treated with cotrimoxazole. However, this patient is near term and the sulfa in the cotrimoxazole might put the infant at risk due to kernicterus. Thus, the first generation cephalosporin, cefadroxil, is appropriate since it would be effective orally against penicillinase producing E. coii. Ceftriaxone, while it would be effective, would have to be administered parenterally. Penicillin V is not effective against E. coii. Tetracycline deposits in teeth and skeleton of the fetus and is contraindicated. 

Aminoglycosides are poorly absorbed from the gastrointestinal tract, so when used systemically they must be given parenterally. Note that penicillins or cephalosporins can inactivate aminoglycosides if mixed together in the same solution fiar injection or fiar topical application each drug must be administered separately. If topical fortified cefazolin and fortified tobramycin are used to treat a corneal ulcer, each should be prepared and administered in a separate bottle. 

These are adapted from the ampicillin molecule, with a side-chain derived from urea. Their major advantages over the carboxypenicillins are higher efficacy against Pseudomonas aeruginosa and the fact that as monosodium salts they deliver on average about 2 mmol of sodium per gram of antimicrobial (see above) and are thus safer where sodium overload should particularly be avoided. They are degraded by many p-lactamases. Ureidopenicillins must be administered parenterally and are eliminated mainly in the urine. Accumulation in patients with poor renal function is less than with other penicillins as 25% is excreted in the bile. An unusual feature of their kinetics is that, as the dose is increased, the plasma concentration rises disproportionately, i.e. they exhibit saturation (zero-order) kinetics. 

Patients with abnormal CSF findings should be treated as having neurosyphilis. Preferred regimens for neurosyphilis provide treatment over 10 to 14 days with parenteral penicillin G administered every 4 hours. Benzathine penicillin G alone in standard weekly doses and procaine penicillin G in doses under 2.4 million units do not consis-... 

Cephalosporins are usually administered parenterally. These drugs are the most frequently used for bacterial infections because of their broad activity and low toxicity. The P-lactam antibiotics account for about 60% of the annual worldwide sales of antibiotics amounting to 11 thousand million US dollars. Of this amount, cephalosporins claim 40% and penicillins 20%. 

Sulfonamides and penicillin are administered orally, topically as an ointment or cream, or parenterally and are absorbed into the body and distributed by the circulatory system. In severe infections, they can be administered directly at the site of the infection such as in the eye or mbbed on the skin. 

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